SEOmediumtechnical

Keep linked PDFs under 60 MB

rule · pdf-size

Google indexes PDFs and can show them directly in search results. However, very large PDF files may be truncated during download, resulting in partial indexing of the content, which is why large documents often need an accompanying HTML strategy rather than relying on the PDF alone.

Code Example

Shell

# Check a single PDF's size via HTTP header
curl -I https://example.com/docs/annual-report.pdf | grep -i content-length
 
# Check file size in bytes
# 1 MB = 1,048,576 bytes
# 10 MB = 10,485,760 bytes
# 60 MB = 62,914,560 bytes

Why It Matters

PDFs larger than Googlebot's download threshold are partially crawled or skipped, meaning their content may not appear in search results even when linked from well-indexed pages. That makes file-size control part of the same discoverability work as HTML companion pages and crawl-friendly document delivery.

Googlebot's Size Limits

Google has not published an exact byte limit, but has documented:

Files above 15 MB may have crawling issues
The practical upper limit is approximately 60 MB for content indexing
Very large files are skipped or only the first portion is indexed

Size Targets

File Size	Status
< 5 MB	Ideal
5–15 MB	Acceptable — consider compressing
15–60 MB	At risk of partial indexing
> 60 MB	Likely skipped by Googlebot

Compressing PDFs

Ghostscript (command line):

Shell

gs -sDEVICE=pdfwrite \
   -dCompatibilityLevel=1.4 \
   -dPDFSETTINGS=/ebook \
   -dNOPAUSE \
   -dQUIET \
   -dBATCH \
   -sOutputFile=compressed.pdf \
   original.pdf

PDF settings presets: /screen (72dpi), /ebook (150dpi), /printer (300dpi), /prepress (300dpi+)

Online tools:

Adobe Acrobat (File → Reduce File Size)
Smallpdf, ILovePDF, PDF24

HTML Companion Page Strategy

For critical content in large PDFs, create an HTML landing page:

HTML

<!-- HTML page for the PDF content -->
<article>
  <h1>Annual Report 2024</h1>
  <p>Key findings from our 2024 annual report...</p>
  <!-- full text content here -->
  <a href="/reports/annual-2024.pdf" rel="nofollow">
    Download PDF (8.2 MB)
  </a>
</article>

The HTML page is indexed fully; the PDF link uses rel="nofollow" if you don't need the PDF itself indexed separately.

PDF SEO Best Practices

Add metadata (Title, Author, Subject) to the PDF properties
Ensure the PDF is not password-protected or encrypted
Use descriptive file names: annual-report-2024.pdf not doc123.pdf
Avoid scanned PDFs without OCR — the text is an image and can't be indexed

Exceptions

Necessary utility or compliance pages can be intentionally brief and should not be judged by the same editorial-depth expectations as ranking-focused content.
AI-assisted drafting is not a failure by itself; flag unsupported claims, missing editorial review, or low-originality output instead.
When a page has both trust-signal issues and crawl/index problems, make the page eligible to rank first and then improve the content quality signals.

Verification

Automated Checks

Inspect rendered HTML and HTTP headers to confirm the expected metadata or crawlability signal is present.
Test the affected URL with Google Search Console or equivalent tooling where relevant.
Re-crawl a representative page set after deployment.

Manual Checks

Confirm the change does not create conflicting canonical-url, robots, or structured-data signals.